Lac genes are most effectively expressed in presence of Lactose and its analogs when glucose is absent.
Explanation:
A unit of prokaryotic gene expression and regulation,which includes structural genes and regulatory sequences recognized by regulatory gene product is called operon.
<em>Lac </em>structural genes are a part of<em> Lac</em> operon. The <em>Lac </em>operon consists of three, structural genes,an operator and a promoter.The product of Lac operon is involved in the conversion of disaccharide lactose into glucose and Galactose.
Lactose and its analogs are inducers of<em> Lac </em>operon. So, the structural genes are best expressed in presence of Lactose. Glucose and galactose are repressors of lac gene so the genes are repressed in presence of glucose.
<span>Out of the following given choices;</span>
A. Further antibody attack.
B. Phagocytosis
C. Helper T cells
D. B cells.
E. None of the above.
The answer
is B. Phagocytises is the engulfment of a particle from the external
environment, by a cell, for ingestion. This is especially critical for the
function of macrophages, which are immune cells. These macrophages have receptors
for the Fc region of the immunoglobulin on their cell membrane surface.
Prokaryotic protein synthesis can be fairly fast because one gene can be transcribed and translated simultaneously. Eukaryotic synthesis is slower, but more precious. They can "check" the mRNA before it is translated into protein.
